Traditional wisdom holds that ultra-pulsed CO 2 fractional laser treatment for postoperative scars should be performed after scar maturation. However, the latest evidence suggests that early laser intervention can significantly shorten the duration of the scar immature phase, reduce angiogenesis, and inhibit scar hyperplasia. A growing number of researchers have adopted early laser intervention for postoperative scars, with intervention timings ranging from intraoperative to the inflammatory, proliferative, and remodeling phases of wound healing. These studies have demonstrated that early intervention with ultra-pulsed CO 2 fractional laser for postoperative scars-especially within the first month after surgery-can effectively improve scar appearance, reduce the risk of scar hyperplasia, and lower the incidence of adverse reactions.

Traditional wisdom holds that ultra-pulsed CO 2 fractional laser treatment for postoperative scars should be performed after scar maturation. However, the latest evidence suggests that early laser intervention can significantly shorten the duration of the scar immature phase, reduce angiogenesis, and inhibit scar hyperplasia. A growing number of researchers have adopted early laser intervention for postoperative scars, with intervention timings ranging from intraoperative to the inflammatory, proliferative, and remodeling phases of wound healing. These studies have demonstrated that early intervention with ultra-pulsed CO 2 fractional laser for postoperative scars-especially within the first month after surgery-can effectively improve scar appearance, reduce the risk of scar hyperplasia, and lower the incidence of adverse reactions.

Objective:To evaluate the accuracy and reliability of high frequency ultrasound in measuring the penetration depth of hypertrophic scar with ultra-pulse CO 2 fractional laser. Methods:From February 2022 to February 2023, 10 cases of hypertrophic scar tissue underwent surgical resection in the Hunan Provincial People′s Hospital were collected. After irradiating the hypertrophic scar tissue with different energy ultra-pulse CO 2 dot matrix laser, high-frequency ultrasound was used to observe and identify the laser gasification holes and tissue degeneration areas in the scar. The same scar tissue was histopathically sliced and the images of laser vaporized pores and tissue degeneration area were collected after hematoxylin-eosin (HE) staining, and the correlation and consistency of the two results of high-frequency ultrasound and pathological tissue section were compared and analyzed. Results:There was a strong positive correlation between the results of laser channel depth measured by pathological section and the results of laser channel depth measured by high-frequency ultrasound and the depth of tissue degeneration area ( r=0.976, 0.927, all P<0.001). Among them, the results of pathological section and high-frequency ultrasound measured laser channel depth were highly consistent, and could be used interchangeably in clinical work. Conclusions:High-frequency ultrasound can be used to evaluate the change of scar internal condition after ultra-pulsed CO 2 dot matrix laser irradiation, and measure the penetration depth of laser on scar tissue. The measurement results have high accuracy and reliability.

Objective:To study the effect of gauze filtration on the content of adipose stem cells in fat gel.Methods:In March 2022, fat samples from 5 patients who underwent abdominal fat aspiration at the Hunan Provincial People′s Hospital were collected, prepared fat ged, the fat gel was filtered 1-5 times with 2 layers of gauze, and the amount of fat gel passing through a 1 ml threaded syringe with a 27 G needle was measured after each filtration. At the same time, the content of fat stem cells in the filtered fat gel was detected by flow cytometry.Results:As the number of filters increases, the amount of fat gel passing through gradually increased. The increasing trend was obvious after the first to fourth filters, and the increasing trend slowed down after the fifth filter. After statistical analysis, the differences between the first filter and the second filter, the second filter and the third filter, and the third filter and the fourth filter were statistically significant ( P<0.05). There was no statistically significant difference between the fourth filter and the fifth filter ( P>0.05). As the number of filters increased, the content of adipose stem cells in the fat gel gradually decreased. The decreasing trend was obvious after the first to third filters, and the decreasing trend slowed down after the fourth filter. After statistical analysis, the differences between the first filter and the second filter, as well as the second filter and the third filter, were statistically significant (all P<0.05). However, there was no statistically significant difference between the third filter and the fourth filter, and the fourth filter and the fifth filter (all P>0.05). Conclusions:The more times gauze is filtered, the better the permeability of fat gel. However, the content of adipose stem cells will significantly decrease in the first three filters. Therefore, the number of times gauze is filtered for fat gel should be minimized as much as possible.

Objective:To evaluate the accuracy and reliability of high frequency ultrasound in measuring the penetration depth of hypertrophic scar with ultra-pulse CO 2 fractional laser. Methods:From February 2022 to February 2023, 10 cases of hypertrophic scar tissue underwent surgical resection in the Hunan Provincial People′s Hospital were collected. After irradiating the hypertrophic scar tissue with different energy ultra-pulse CO 2 dot matrix laser, high-frequency ultrasound was used to observe and identify the laser gasification holes and tissue degeneration areas in the scar. The same scar tissue was histopathically sliced and the images of laser vaporized pores and tissue degeneration area were collected after hematoxylin-eosin (HE) staining, and the correlation and consistency of the two results of high-frequency ultrasound and pathological tissue section were compared and analyzed. Results:There was a strong positive correlation between the results of laser channel depth measured by pathological section and the results of laser channel depth measured by high-frequency ultrasound and the depth of tissue degeneration area ( r=0.976, 0.927, all P<0.001). Among them, the results of pathological section and high-frequency ultrasound measured laser channel depth were highly consistent, and could be used interchangeably in clinical work. Conclusions:High-frequency ultrasound can be used to evaluate the change of scar internal condition after ultra-pulsed CO 2 dot matrix laser irradiation, and measure the penetration depth of laser on scar tissue. The measurement results have high accuracy and reliability.

Objective:To explore the therapeutic mechanism of fractional laser combined with pulsed dye laser and multi-point microinjection of triamcinolone in the treatment of hypertrophic scars in rabbit ears.Methods:In this study, 80 hypertrophic scar models of rabbit ears were made and randomly divided into 4 groups: control group, laser combined group, laser combined multi-point microinjection group, simple traditional injection group, 20 scar models in each group.The control group was not given treatment; the laser combined group was treated with pulsed dye laser first, followed by fractional laser at the same time; the laser combined with multi-point microinjection group was treated with pulsed dye laser and fractional laser first, followed by multi-point microinjection of triamcinolone in the scar immediately after laser treatment; the traditional injection group was injected with triamcinolone in the scar.The gross appearance of hypertrophic scars was observed and recorded in 4 groups. At 7 days and 2 months after treatment, the hypertrophic scars were cut and the histological study were performed by HE staining; the expression of collagen was observed by Masson staining and the volume fraction of collagen was measured; the number of micro-vessels was observed by CD31 staining and the micro-vessel density was measured.One way ANOVA was used to show the difference between groups, LSD posthoc test was used to compare between groups, and Pearson correlation coefficient was used to analyze collagen volume fraction and micro-vessel density.Results:Two months after the treatment, the histological results showed that the scar thickness of the laser combined group and the laser combined with multi-point microinjection group was significantly thinner than that of the control group, the texture of the scar was softened, the red color gradually became lighter, and approached to the color of the surrounding skin. Compared with the control group, the scar in the traditional injection group was thinner, softer and lighter. The scar thickness of laser combined with multi-point microinjection group was thinner than that of laser combined group and simple traditional injection group.Masson staining was used to calculate the collagen volume fraction (CVF): the expression of CVF in hypertrophic scar tissue of each group was reduced. The CVF values of each group at the 7th day and the 2nd month were compared. There was statistically significant difference between the laser combined group, the laser combined multi-point microinjection group and the simple traditional injection group ( P<0.05), but there was no statistical difference between the control group ( P>0.05). The CVF value of each group was further compared at 2 months after treatment, the laser combined multi-point microinjection group 0.05). 2 months after treatment, the MVD values of each group were compared with the result as the laser combined with multi-point microinjection group < laser combined group < simple traditional injection group, but there was no statistical difference between the laser combined with multi-point microinjection group and the laser combined group ( P>0.05). There was statistical difference between the laser combined with multi-point microinjection group and the laser combined group and the simple traditional injection group ( P< 0.05). The Pearson correlation coefficient was r=0.972, which indicated that there was a positive correlation between the collagen content and the number of micro-vessels. Conclusions:The use of fractional laser combined with pulsed dye laser and multi-point microinjection of triamcinolone in the treatment of hypertrophic scars in rabbit ears can evenly reduce the number of fibroblasts, promote the normalization of collagen density and arrangement, and reduce collagen volume fraction and micro-vessel density. The curative effect is better than fractional laser combined with pulse dye laser therapy and simple traditional triamcinolone injection therapy. There is a positive correlation between collagen content and micro-vessel density in hypertrophic scars. Simultaneously inhibiting the proliferating blood vessels can improve the therapeutic effectiveness.

Objective:To explore the therapeutic mechanism of fractional laser combined with pulsed dye laser and multi-point microinjection of triamcinolone in the treatment of hypertrophic scars in rabbit ears.Methods:In this study, 80 hypertrophic scar models of rabbit ears were made and randomly divided into 4 groups: control group, laser combined group, laser combined multi-point microinjection group, simple traditional injection group, 20 scar models in each group.The control group was not given treatment; the laser combined group was treated with pulsed dye laser first, followed by fractional laser at the same time; the laser combined with multi-point microinjection group was treated with pulsed dye laser and fractional laser first, followed by multi-point microinjection of triamcinolone in the scar immediately after laser treatment; the traditional injection group was injected with triamcinolone in the scar.The gross appearance of hypertrophic scars was observed and recorded in 4 groups. At 7 days and 2 months after treatment, the hypertrophic scars were cut and the histological study were performed by HE staining; the expression of collagen was observed by Masson staining and the volume fraction of collagen was measured; the number of micro-vessels was observed by CD31 staining and the micro-vessel density was measured.One way ANOVA was used to show the difference between groups, LSD posthoc test was used to compare between groups, and Pearson correlation coefficient was used to analyze collagen volume fraction and micro-vessel density.Results:Two months after the treatment, the histological results showed that the scar thickness of the laser combined group and the laser combined with multi-point microinjection group was significantly thinner than that of the control group, the texture of the scar was softened, the red color gradually became lighter, and approached to the color of the surrounding skin. Compared with the control group, the scar in the traditional injection group was thinner, softer and lighter. The scar thickness of laser combined with multi-point microinjection group was thinner than that of laser combined group and simple traditional injection group.Masson staining was used to calculate the collagen volume fraction (CVF): the expression of CVF in hypertrophic scar tissue of each group was reduced. The CVF values of each group at the 7th day and the 2nd month were compared. There was statistically significant difference between the laser combined group, the laser combined multi-point microinjection group and the simple traditional injection group ( P<0.05), but there was no statistical difference between the control group ( P>0.05). The CVF value of each group was further compared at 2 months after treatment, the laser combined multi-point microinjection group 0.05). 2 months after treatment, the MVD values of each group were compared with the result as the laser combined with multi-point microinjection group < laser combined group < simple traditional injection group, but there was no statistical difference between the laser combined with multi-point microinjection group and the laser combined group ( P>0.05). There was statistical difference between the laser combined with multi-point microinjection group and the laser combined group and the simple traditional injection group ( P< 0.05). The Pearson correlation coefficient was r=0.972, which indicated that there was a positive correlation between the collagen content and the number of micro-vessels. Conclusions:The use of fractional laser combined with pulsed dye laser and multi-point microinjection of triamcinolone in the treatment of hypertrophic scars in rabbit ears can evenly reduce the number of fibroblasts, promote the normalization of collagen density and arrangement, and reduce collagen volume fraction and micro-vessel density. The curative effect is better than fractional laser combined with pulse dye laser therapy and simple traditional triamcinolone injection therapy. There is a positive correlation between collagen content and micro-vessel density in hypertrophic scars. Simultaneously inhibiting the proliferating blood vessels can improve the therapeutic effectiveness.

Objective:To explore the effect of combined application of pulsed dye laser (PDL) and ultra-pulsed fractional carbon dioxide laser (UFCL) in the treatment of pediatric large burn scars at early stage.Methods:One hundred and twenty pediatric patients with large burn scars at early stage conforming to the study criteria were admitted to the People′s Hospital of Hunan Province from January 2016 to December 2019. Their data were retrospectively analyzed by the method of single case-control study. There were 78 males and 42 females with age of (4.2±0.8) years and scar area of (100.3±0.7) cm 2. PDL combined with UFCL was used for the first time. The treatment interval of PDL was a month and the treatment interval of UFCL was 3 months. The total treatment cycle was 6 months, with 2 PDL treatments alone and two combined treatments. Before the first combined treatment and 6 months after two combined treatments, the curative effect was assessed using Patient and Observer Scar Assessment Scale (POSAS) by doctors and family members of pediatric patients. Satisfaction degrees of the family members of pediatric patients were recorded, and the overall satisfaction rate was calculated 6 months after two combined treatments. The adverse effects during the whole treatment course were recorded. Data were statistically analyzed with paired t test. Results:(1) Six months after two combined treatments, the scores of pediatric patients′ scar vascularity, pigment, thickness, relief, pliability, surface area, and overall valuation in POSAS by doctors and the scores of pain, itch, color, stiffness, thickness, irregularity, and overall valuation in POSAS by family members of pediatric patients were all significantly lower than those before the first combined treatment ( t=16.6, 16.0, 16.9, 14.9, 20.8, 29.3, 30.7, 20.4, 29.3, 18.1, 27.9, 25.8, 20.8, 45.3, P<0.01). The overall evaluation scores by doctors were (8.1±0.8) and (2.7±0.6) points, and the overall evaluation scores by family members of pediatric patients were (8.2±0.8) and (2.4±0.5) points respectively before the first combined treatment and six months after two combined treatments. (2) Six months after two combined treatments, 110 (92%) family members of pediatric patients were very satisfied with the curative effect, 6 (5%) family members of pediatric patients were satisfied, and 4 (3%) family members of pediatric patients were relatively satisfied with no unsatisfied reported. The overall satisfaction rate was 97% (116/120). (3) During the treatment, pruritus and rash appeared in 5 pediatric patients 3 to 4 days after the first treatment; pigmentation appeared in 3 pediatric patients 3 weeks after the first treatment; pruritus and vesicle appeared in 1 patient 1 week after the third treatment. No adverse effects such as aggravated scar or infection were observed on the wounds. Conclusions:In treating pediatric large burn scars at early stage, PDL combined with UFCL has demonstrated significant effect with short treatment cycle, few adverse effects. The combined treatment can alleviate symptoms and improve the quality of pediatric patients′ life, and is worthy to be popularized and applied in clinic.

The prevention and treatment of scars has always been an important task in the field of wound repair.Humans have started treatment for scars long time ago and have created a series of treatments.At the same time,with the development of science and technology,the diagnosis and treatment of scars have made great progress.Through the basic research for new therapeutic targets and innovative of treatment methods,treatment for scar turns more diversified and integrated.As a result,clinicians will suffer many challenges while having more options for scars treatment.Combined with traditional treatment,developing new treatments,and the comprehensive therapy of multiple treatment methods is the mainstream trend of scar treatment.

Objective To investigate the clinical effect of 595 nm tunable pulsed dye laser (PDL) in treating fresh trauma scars.Methods 85 patients had been selected,of which,117 sites were treated with a 595 nm tunable PDL one time or two times at a fluence of 7-15 J/cm2 and pulse widths of 1.5-3 ms,7 mm spot size.Nursing skill of burn wound was also used on treatment area after laser treatment.Scars were evaluated for melanin,height,vascularity and pliability using the Vancouver Scar Scale (VSS) before treatment and after the last treatment 8weeks.Results Total score of 117 sites decreased from (8.30 ± 2.63) to (2.70 ± 1.25),melanin decreased from (1.60 ± 0.84) to (0.60 ± 0.97),height decreased from (1.30 ± 0.82) to (0.40 ± 0.51),vascularity decreased from (2.40 ± 0.52) to (0.40 ±0.52),pliability decreased from (2.80 ± 1.32) to (1.30 ±0.48),with statistical significance between before treatment and after treatment (P ＜ 0.05).Conclusions 595 nm tunable pulsed dye laser appears to have a beneficial clinical effect on patient's fresh trauma scar.